The molecular mechanisms involved in regulation and function of the Myoc/Tigr gene were studied. The minimal promoter (- 234/+54) of the human gene was identified. This promoter drives the expression of reporter genes in transfected C2C12, N/N1003 and MUTM-NEI/1 cells in vitro and has a specific expression pattern in transgenic mice in vivo. A comparison of hybridization with gene array filters, comparative analysis of the human, mouse and rat Myoc/Tigr promoters, a candidate gene approach, and mutational analysis of the human promoter allowed us to identify several transcription factors potentially involved in the regulation of the human MYOC/TIGR gene. Interaction of these factors with the Myoc/Tigr promoter is under investigation. Using green fluorescent protein as a tag, we have shown that the Myoc/Tigr protein is co-localized with microtubules in the cell cytoplasm. All the fragments tested with a length of at least 40 amino acids located between positions 1-124 and 15-138 in the mouse and human proteins, respectively, provided cytoplasmic localization of the protein. We have shown that Myoc/Tigr is a secreted protein by injection of Myoc/Tigr mRNA in Xenopus oocytes. A rat model of glaucoma was established which is presently being tested. - eye, glaucoma, trabecular meshwork, myocilin, tigr,green fluorescent protein, animal model, transgenic animal, promoter